call humana at 1-800-808-4003. bill: a new challenge now as states legalize marijuana for medical and recreational use. law enforcement agent size now working to develop driving limits like those you find for alcohol. pot officially becomes legal in washington state as of today, where there is already a driving limit in place. what is that limit? william la jeunesse live on that story in our west coast newsroom. william, good morning. >> reporter: bill, the purpose of course is to keep impaired drivers off the road, not bust pot smokers. there is no nation-wide limit on marijuana like alcohol .08. washington's new standard for drug driving is new and controversial. >> you want to know why i pulled you over, littering and smoke being the reefer. >> driving while high, while illegal research shows more drivers are toebgin toking. studies like this one in europe shows too much marijuana affects judgment. marijuana advocates argue pot is far less today bill taeugt than alcohol. a new study says those who drive within t